1. Field of the Invention
The present invention relates to an ink jet recording medium
2. Description of the Related Art
A recording medium having an ink receiving layer on a substrate is known as a recording medium on which recording is conducted by an ink jet recording apparatus. The ink receiving layer is required to rapidly absorb ink. Occurrence of color unevenness on an image can be inhibited by rapidly absorbing ink. As such an ink jet recording medium, there is a recording medium described in International Publication No. WO2007/043713. The recording medium described in International Publication No. WO2007/043713 is such that the ink receiving layer on the substrate has a lower layer and an upper layer, and the thickness ratio of the lower layer to the upper layer and the weight ratio of alumina used in the upper and lower layers are controlled to improve ink absorbency.
In recent years, the ink jet recording medium has been required to have high-speed printability, and so there has been need to improve the conveying accuracy of the recording medium by holding the recording medium between conveying rollers to convey the recording medium. In order to improve the conveying accuracy, it is favorable to use hard conveying rollers hard to be deformed even when the recording medium is held. When such hard conveying rollers are used for the recording medium, however, roller mark of the conveying roller is liable to be left on the recording medium. The roller mark is entirely different in appearance from common scratch defects or flaws caused by applying a load like a pencil hardness test and is an aggregate of minute dimples of 0.1 μm to 5.0 μm in diameter and 0.1 μm to 5.0 μm in depth. The roller mark is considered to be a transfer mark caused when plastic deformation is caused on a conveying roller during printing and then the conveying roller on the surface of which minute projections are thus produced comes into contact with the surface of the recording medium. In the recording medium described in International Publication No. WO2007/043713, such roller mark as described above has been caused in some cases when high-speed printing has been conducted thereon by means of an ink jet recording apparatus.
In addition, in the recording medium described in International Publication No. WO2007/043713, color unevenness has been caused on a resulting image in some cases when such high-speed printing as required in recent years has been conducted. The color unevenness is considered to be caused because ink absorption sufficient for the high-speed printing cannot be attained.
In view of the foregoing problems, it is an object of the present invention to provide an ink jet recording medium which inhibits the occurrence of roller marks and rapidly absorbs ink to inhibit the occurrence of color unevenness on an image even when high-speed printing is conducted by an ink jet recording apparatus.